With features and feature rules.
I have 96 custom flowers spawning in different biomes.
Create a single_block_feature for each flower
Create a weighted_feature to include the single_block_features you have made for your flowers
Create a feature rule to include the weighted feature(you can choose in this feature rule in what biome you want your flowersz to appear).
It's a world generation question more than a block question.
If you are struggling to do it, please post there, I could post some examples
#how to make custom blocks appear naturally, like flowers
charred tiger
modern lily
Sorry, I don't understand at all. Can you give an example?
charred tiger
You need to create two folders in your BP
features
feature_rules
I will give you my code for flowers spawning in meadow biome
charred tiger
We are in the wrong place tho, it's a world generation question, could you please make another post there? I will give you all the details